Tetrahydrofuran (hereinafter, sometimes simply referred to as “THF”) has been heretofore used as a solvent for various organic compounds and in addition, is known to be a compound useful also as a raw material monomer of a polyether polyol such as polytetramethylene ether glycol.
As the industrial production method of a cyclic ether such as tetrahydrofuran, a variety of production methods are known. Among others, the cyclic ether is produced in many cases by performing a cyclodehydration reaction of a dihydroxy compound. In this cyclodehydration reaction of a dihydroxy compound, an acid catalyst exhibiting a high conversion ratio and a high selectivity is generally used as the catalyst. For example, Patent Document 1 describes a method of dehydrogenating and dehydrating an alkanediol such as 1,4-butanediol (hereinafter, sometimes simply referred to as “1,4BG”) in the presence of a cobalt-containing catalyst, an organic sulfonic acid and a high-boiling-point amine to produce an α,β-cyclic unsaturated ether such as dihydrofuran. In addition, Patent Document 2 describes a method for continuously producing THF by a reaction of a 1,4-butanediol-containing reaction mixture on a heteropolyacid catalyst. The reactor type when performing a cyclodehydration reaction of 1,4BG by using such a catalyst to produce THF includes, for example, a liquid phase reactor using a fixed bed reactor, and a reaction distillation type where the product is distilled off from the reactor through a vapor phase portion.
Background Art Document
Patent Document
Patent Document 1: JP-A-10-77277 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)
Patent Document 2: JP-T-2006-503050 (the term “JP-T” as used herein means a published Japanese translation of a PCT patent application)